Explosively actuated fastener driving tool



Sept. 24, 1-963 P. TERMET EXPLOSIVELY ACTUATED FASTENER DRIVING TOOL 2 Sheets-Shae 1 Filed June 28, 1961 m cm 3 1 AM Le Sept. 24, 1963 P. TERMET 3,104,395

EXPLOSIVELY ACTUATED FASTENER DRIVING TOOL Filed June 28, 1961 2 Sheets-Sheet 2 Manley s 3,104,396 EXPLOSIVELY AQTUATED FASTENER DG TOOL Pierre 'Iermet, 16 Impasse Belloeuf, Lyon, France Filed June 28, 1961, Ser. No. 129,374 Claims priority, application France Jane 29, 1960 2 Claims. (\Il. 144.5)

of the said apparatus; said shank permits the driving of the stud when one strikes its head with a hammer.

It is the object of the invention to provide an explosively actuated fastener driving tool comprising a number of interchangeable barrels which are adapted to drive studs of different types or gauges and to be driven by an explosive charge.

Another object of this invention is to provide an explosively actuated fastener driving tool comprising essentially: a body for receiving an explosive cartridge and a means for firing said cartridge; barrels of different sizes adapted to be screwed on said body; a piston freely movable inside the barrel for propelling the stud, the forward movement of said piston being stopped with its forward end projecting from the barrel when a shoulder thereon encounters a mobile section of the front portion of the barrel, said mobile section preferably uncovering a side opening provided for the direct expulsion of the propulsion gases as soon as the forward end of the piston passes out of the barrel, providing therefore a braking action on the movement of said piston.

According to the preferred embodiment of this invention, the mobile part located at the end of the barrel comprises several parts which are each movable with respect to the other and among those parts, one which bears against the shoulder of the piston compresses a part made of an elastic (such as a plastic substance known under the trademark Rilsan) which, through the deformation caused by its compression stronglybrakes the movement of said free piston.

According to the invention, the aforesaid different barrels may be mounted on the body of a manually operated apparatus for driving studs of different sizes by means of repeated percussions.

Still another object of the invention is a safety device for an explosively actuated fastener driving tool, preferably of the aforesaid type, said safety device comprising essentially a spring loaded actuator having for striking the head of the firing pin, said actuator acting on the firing pin only if the front end of the'barrel is pressed with sufficient strength against the material in which the stud is to be driven and if the operator maintains pressure on a knob or button located near the rear part of the barrel.

With these and other objects in view, the invention consists in the constructions, arrangement and combinations of various parts of the device whereby the objects contemplated are attained, as hereafter more fully set forth, pointed out in the claims and illustrated in the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional view of one embodiment of the fastener driving tool according to the invention;

ddfi lgdfifi Patented Sept. 24., 19%3 FIG. 1a is a partial section of the fastener driving tool of the FIG. 1, with the end part of the barrel projecting out;

'FIG. 2 is an end view of the barrel of the fastener driving tool shown in the FIG. 1;

FIG. 3 is a cross-section showing the safety device as seen along the line III-III of the FIG. 1;

FIG. 4 shows a longitudinal sectional view of the front head of the fastener driving tool on which is mounted one barrel; 5

FIG. 5 represents a sectional view of the front head of the fastener driving tool on which is mounted a barrel of a different type than the one shown in FIG. 4;

FIG. 6 is an end view of the barrel illustrated in FIG. 5;

FIGS. 7 and '8 show how the barrels represented on FIGS. 4 and 5 are mounted on the body of a manually actuated apparatus;

FIG. 9 is a longitudinal sectional view of the head of barrel in which the mobile part contains a means for braking the movement of the freely movable piston;

FIGS. 10 and 11 illustrate two other embodiments of the brake shown in the FIG. 9.

As shown in FIG. 1, the body 1 of the fastener driving tool comprises inside a bore 2 a percussion bushing 3 adapted to slide coaxially in said bore. A loaded spring 4 biasses the percussion bushing 3 forwardly the movement of said bushing being limited by the screw 5 having its end 5a engaged in a longitudinal groove 6 cut in the percussion bushing.

Under these conditions the percussion-bushing 3 lies normally in the position shown in FIG. 1, but if a sumcicnt pressure is applied to the said percussion bushing to compress the spring 4, said bushing moves until its shoulder 3a contacts the shoulder 11a provided in the body of the fastener driving tool.

As will be explained hereinafter the movement irn-.

parted to, the percussion bushing plays a part in the functioning of the whole system designed for insuring safety in the use of the fastener driving tool and avoiding the possibility that said driving tool could be used as a weapon.

The percussion bushing contains a firing pin 7 kept prisoner inside its tbone by the hollow nut 8. One end 7a of the firing pin 7 is positioned near the percussion zone of thecartridge 9 whereas its other end -.7 b protrudes towards the actuator 10, which is constantly biased towards the firing pin by a coaxial percussion spring.

Thus, the actuator 10 cannot in any case reach the firing pin 7 when the apparatus is in the position shown in FIG. 1, i.e. when the end of the barrel is not applied against the material into which a stud is to be driven. FIG. 3 illustrates the body 1 of the apparatus and the actuator 10 provided with a circular groove Illa. A stop 11 may be moved in a radial bore 12 cut in the body 1 under the action of .a lever 13 swinging at 14, said lever being constantly pushed back by the spring 15 soas to bring back in the groove 10a the end 11a of the stop 11.

Under these conditions, in order to move the actuator 10 in'the direction :of the arrow F by means of the ring 10b, it is necessary to first move the lever 13 in the direction of the arrow F so as to pull the .end 11a of the stop 11 out of the groove ltla'of the actuator 10'. For firing one should first apply the barrel muzzle against the material in which the stud is to be fixed; this operation moves the percussion bushing to the left isde of FIG. 1.

Then the operator, holding with his hand the [body of the apparatus, presses the lever 13 in the direction of the arrow P with his finger whereas simultaneously with his other hand pulling out the actuator by its ring 10b, in the direction of the arrow F.

When the percussion spring is sufiiciently compressed the device is fired by simply releasing the actuator.

It is to be noted that the lever 13 is located near the rear part of the body of the fastener driving tool to avoid the possibility that the user may, with one hand, act on this lever 13 and keep the front part of the driving tool in the position where the spring 4 is totally compressed, such condition :being dangerous since it makes firing possible and would allow the operator to use the apparatus :as a weapon.

Practically, after each firing, the end 11a oi the stop It always comes back into the groove 10a of the actuator 10 by reason of the backward movement of the tool; that makes firing impossible unless continuous pressure is applied on the lever 13. V

In any event, accident-a1 dropping of the loaded tool does not give raise to the risk of an accidental firing.

because the rear end of the actuator is surrounded by the annular part 112 of the body 1 protecting the actuator from any impact. v

As shown in FIG. 1 the groove liia is connected to the percussion or firing section of the actuator by a conical slope which makes it easier for the stop 11 to come into the groove when permanent pressure is not applied on the lever 13.

The barrel 16 is screwed on the percussion bushing 3 by means of the threads 1611, sufiicient room being left between those two parts to permit the positioning of the head of the cartridge 9. The barrel 16 comprises three essential parts 17, 18 and 19 assembled by screwing, a lock 20 locking the part 1'7 into the part 18.

Such a barrel structure makes possible the introduction into the barrel of the piston 21 which remains as a prisoner in the barrel but may still axially slide in said barrel.

This piston 21, the central part of which has the same diameter as the internal bore of the barrel, is provided with a first cylindrical end 21a having a reduced cross section which enters into the explosion chamber in order to reduce the capacity of said chamber so as to increase the explosive power and facilitate the firing, and with a second end 21b having a diameter slightly inferior to that of the central part, said second end, as hereinafter explained, being capable of being projected from the barrel with the shoulder which connects the end section 21b with the central section of the piston bearing against the shoulder 22 provided in the end part or muzzle 23 of the barrel.

An annular magnet 24 located in a cup 25-26 keeps the stud 27 in position before firing. The end part 23 which is provided with the shoulder 22 is slidably locked on the section 19 of the barrel by the screw 28 the head of which slides in an elongated slot 29 running in a parallel direction to the barrel axis.

Therefore, when the piston 21 passes out of the barrel as a consequence of the recoil of the tool, it carries forward the muzzle 23 until it reaches the position shown in FIG. la. In that position the explosive gases escape directly from the opening 29 which is then uncovered.

On the other hand, by reason of the escape of the propelling gases, the muzzle 23 (the forward movement of which is limited by the screw 28 striking against the section 19 of the barrel) is enabled to stop the movement of the piston which comes to rest against the shoulder 22 at the junction point between its central part and forward end 21b.

As shown also in the drawing the magnet30 fixed on the muzzle 23 by a screw 31 is useful for holding in position the'fastening washers, the stop washers or clamps put, before firing, in the shallow recess 32 made at the end of the barrel for that purpose.

According to the invention a second circular recess 33 is made in the muzzle 23; said recess 33 serves to receive at the front end of the barrel fastening washers having a smaller diameter which are also kept in position by the magnet 30.

FIG. 4 illustrates the right end member of a fastener driving tool of the type shown in FIG. 1, on which is mounted a barrel end of a difierent type.

In FIG. 4 is shown again the part 17 of FIG. 1 and the lock-nut 20, but the parts 18 and 19 of the barrel illustrated in FIG. 1 are replaced by a cylindrical tube 34 screwed into the part 17 of the barrel.

This makes it possible to drive in a very simple manner studs with screwed trends such as the studs 35 illustrated in FIG. 4. To that purpose a piston 36 provided with a sealing washer 37 and to which the stud 35 may be screwed is inserted inside the tube 34.

The piston 36 has an extension 36a projecting into.

the explosive chamber in order to reduce the capacity of said chamber. The said piston is also provided with a lateral groove 3% for limiting the power and allowing the escape of the propellant gases as-soon as the piston projects a fixed distance out of the tube 34.

At the time of firing, the piston and the stud are located in the position shown in FIG. 4 and, when the car tridge is fired the piston 36 is pushed forwardly and drives the stud 35 equipped with its stop washer 35a into the material.

After firing, since the piston 36 projects out of the tube, one needs only to unscrew the piston 36 in order' to reuse the apparatus.

When more power is needed, it is possible to use a piston 36 without any groove 38. Such a device, the construction of which is very simple, makes possible a very precise driving of studs with threaded heads which, as

one knows, are much more difiicult to use than the others due to the crushing of the threads which commonly occurs during the firing.

FIG. 5 illustrates a portion of the driving tool shown in FIG. 1; on that portion is mounted a barrel end 39- which makes it possible to drive studs having smaller diameters the ends of which are adapted to fasten halfclamps.

In FIG. 5, are illustrated the portion 17 of the driving tool and the clamping ring 20 shown in FIG. 1. Between the portion 39 of the barrel and the portion 17 is located an intermediate ring 40 provided with a shoulder.

they are fastened. Such a half-clamp is shown in FIG.

5 by a broken line.

In the embodiment illustrated in FIG. 5 the cylindrical magnet 24 is replaced by a ball 42 which is loaded by a spring 43 and serves to keep the stud 27 in position before firing. In the different embodiments according to this invention the piston which is used as anintermediate means between the propellan-t charge and the stud may or may not have a fiat part dependent upon;

whether or not it is desired to reduce the power applied to the stud.

Therefore if one has several pistons adapted toeach caliber he can, in choosing the piston, adapt the power to the work done.

The tastener driving tool according to the invention gives the advantage of permitting an easy ejection of the cartridge cases after the firing without needing to use any mechanical device specially designed for that purpose.

The ejection is done automatically when, after un screwing the body 1 of the apparatus, the piston is pushed back by a pushing-rod in order to return it to its firing position.

Through this movement the air contained in the barrel between the piston at the cartridge case is compressed resulting in the automatic ejection of the case.

FIGS. 7 and 8 illustrate the barrel ends shown in FIGS. 1 and mounted on the body of a manually operated apparatus.

One can see in FIG. 7 the parts 18 and 19 of the end of barrels secured on the body 44 of a manually operated apparatus, and held in place by a lock-nut 26.

The body 44- of the apparatus carries a push rod 45 held in place by the screw 46, the end of which moves in the groove 45a in the push rod.

When one strikes on the head 45b of the push-rod, the piston 21 moves and progressively drives the stud 27 in the material.

In order to prevent the push-rod 45 from coming back under the action of gravity or in reaction to blows thereagainst the body 44- is provided with a ball device 44a which brakes the push-rod.

In FIG. 8 are seen the same elements except that the end 450 of the push-rod 45 itself drives the stud 27 without the intermediary means consisting of a piston 21-.

In this embodiment the ball 42 mounted on the barrel brakes the push-rod 45.

FIG. 9 illustrates a device assuring a progressive braking of the freely movable piston 21 and also a progressive driving of the end part or muzzle 23.

To that purpose this muzzle 23 is provided with a recess having a generally cylindrical form inside which is located a ring 46 made of an elastic material such as the material known under the trademark Rilsan.

This ring has a conical shape and its smaller base is directed towards the tool muzzle.

Its internal diameter is equal to the diameter of the part 2112 of the piston.

Inside the muzzle 23 is also located a second metallic ring which bears directly against the elastic ring 46; the internal recess of said ring 47 mates with the portion of the freely movable piston between its central zone and the end 21b of said piston.

The ring 47 performs the function of the shoulder 22 seen in FIG. 1.

It should be noted that in this embodiment the shoulder is preferably made in a frusto-conical shape with a small opening angle.

The end part 23 encloses a movable sleeve 48 which guides the ring 47 and which may slide inside the muzzle 23 owing to a slot 49 which receives the end of the screw 28.

Therefore the sleeve 48 and the ring 47 may move axially and independently with respect to the muzzle 23 which itself may move axially with respect to the driving tool.

When, following a setting mistake which generally comes from the use of too large a charge for the work to be done, the freely movable piston 21 shows a tendency to protrude towards the outside of the apparatus; said piston 21 bears first against the ring 47 which it drives easily forward due to the relatively weak inertia of said ring. The latter then axial-1y compresses the elastic ring 46 which, by reason of the conical shape of its seat reacts immediately to bring radial pressure strongly braking the section 2112 of the piston and simultaneously driving forward the muzzle 23 which in its turn drives the sleeve 48 when the screw 28 comes at the end of the cut 49 made in said sleeve.

Thus, by means of said feature of this invention, the freely movable piston is stopped first because it is progressively locked with a number of parts having more weight than itself and braking it by inertia and secondly because it is held back by the friction developed on its walls by the elastic ring 46 when compressed.

FIGS. 10 and 11 illustrate different possible shapes for the ring 46 each of course requiring appropriate modification of the ring seat in the muzzle 23.

In case of elastic rings as seen in FIGS. 10 and 11 the braking action on the freely movable piston is not effectuated by friction but solely due to the fact the axial compression of the rings results in progressive driving of the muzzle 23, thus preventing too hard a blow by said piston against said muzzle.

Although I have shown and described preferred embodiments of my invention, it will be understood that certain parts and elements thereof may be replaced by mechanical equivalents without departing from the spirit of my invention.

Consequently, I do not intend to be limited to the specific embodiments shown and described but desire to be alforded the full scope of the following claims.

What I claim is:

1. An explosively actuated tool for driving studs, fasteners, and the like, said tool comprising a barrel for receiving an article to be driven, means located rearwardly of the barrel for exploding a propellant charge, a piston carried in said barrel with one end positioned to receive an impact when said charge is exploded and its other end positioned to transmit said impact to said article, said barrel comprising an end portion at its forward end which is axially slidable relative to the remainder of said barrel, cooperating fixed stop means on said end portion and on the remainder of said barrel which limit said relative sliding thereby defining forward and rearward positions for said end portion relative to the remainder of said barrel, said end portion being provided with an inwardly projecting shoulder and said piston with a radially projecting shoulder which overlaps said inwardly projecting shoulder to prevent said piston from passing completely out of said barrel when said piston is projected forwardly therein, and said barrel being provided with a vent for permitting the escape of explosive gases therefrom to the ambient atmosphere, said vent being p ositioned to be open when said end portion is in its forward position relative to said barrel but closed when said end portion is in its rearward position with respect thereto.

2. An explosively actuated tool as claimed in claim 1 in which the effective transverse cross-section of a portion of said piston is peripherally reduced over an axial distance less than the length of the piston and beginning at its rear end, thereby pnoviding a space between that portion of said piston and said barrel which comes into radial alignment with said vent as said piston moves forward and forms with said vent a passage through which gas may escape from said barrel to reduce the force applied to said piston.

References Cited in the file of this patent UNITED STATES PATENTS 2,221,157 Temple Nov. 12, 1940 2,660,726 Weingart Dec. 1, 1953 2,724,116 Termet Nov. 22, 1955 3,019,440 Kopf Feb. 6, 1962 FOREIGN PATENTS 1,109,600 France Sept. 28, 1955 213,498 Australia Mar. 6, 1958 

1. AN EXPLOSIVELY ACTUATED TOOL FOR DRIVING STUDS, FASTENERS, AND THE LIKE, SAID TOOL COMPRISING A BARREL FOR RECEIVING AN ARTICLE TO BE DRIVEN, MEANS LOCATED REARWARDLY OF THE BARREL FOR EXPLODING A PROPELLANT CHARGE, A PISTON CARRIED IN SAID BARREL WITH ONE END POSITIONED TO RECEIVE AN IMPACT WHEN SAID CHARGE IS EXPLODED AND ITS OTHER END POSITIONED TO TRANSMIT SAID IMPACT TO SAID ARTICLE, SAID BARREL COMPRISING AN END PORTION AT ITS FORWARD END WHICH IS AXIALLY SLIDABLE RELATIVE TO THE REMAINDER OF SAID BARREL, COOPERATING FIXED STOP MEANS ON SAID END PORTION AND ON THE REMAINDER OF SAID BARREL WHICH LIMIT SAID RELATIVE SLIDING THEREBY DEFINING FORWARD AND REARWARD POSITIONS FOR SAID END PORTION RELATIVE TO THE REMAINDER OF SAID BARREL, SAID END PORTION BEING PROVIDED WITH AN INWARDLY PROJECTING SHOULDER AND SAID PISTON WITH A RADIALLY PROJECTING SHOULDER WHICH OVERLAPS SAID INWARDLY PROJECTING SHOULDER TO PREVENT SAID PISTON FROM PASSING COMPLETELY OUT OF SAID BARREL WHEN SAID PISTON IS PROJECTED FORWARDLY THEREIN, AND SAID BARREL BEING PROVIDED WITH A VENT FOR PERMITTING THE ESCAPE OF EXPLOSIVE GASES THEREFROM TO THE AMBIENT ATMOSPHERE, SAID VENT BEING POSITIONED TO BE OPEN WHEN SAID END PORTION IS IN ITS FORWARD POSITION RELATIVE TO SAID BARREL BUT CLOSED WHEN SAID END PORTION IS IN ITS REARWARD POSITION WITH RESPECT THERETO. 